1. Field of the Invention
This invention relates to a mid-mount mower having a mower unit disposed between front wheels and rear wheels. More particularly, the invention relates to a mid-mount mower having a function for jacking up a front portion of a vehicle body to expose a blade-equipped plane of a mower unit.
2. Description of the Related Art
In a conventional mid-mount mower noted above, it is necessary to raise the front portion of the vehicle body and expose the inside of the mower unit for inspection and maintenance of interior parts of the mower unit kept mounted on the vehicle body. For this purpose, the mid-mount mower known from U.S. patent application published under No. 2002/0157369 has a jack member pivotably switchable between a storage position retracted toward the vehicle body and an operative position extended forwardly and downwardly of the vehicle body. When switched to the operative position, the jack member is vertically pivotable about its connection to the vehicle body, with a toothed portion formed on the extreme end of the jack member engaging the ground. As the vehicle moves forward with the jack member switched to the operative position, the jack member in the operative position pivots about the toothed portion thereof to an erected posture. This raises the front portion of the vehicle body, thereby exposing the inside of the mower unit.
However, in order to raise the front part of the vehicle body, the operator has to drive the vehicle so as to ride on the jack member that pivots to the erected posture as the vehicle moves forward. Such an operation often arouses a sense of uneasiness in the operator.
A height to which the front of the vehicle body is raised is determined by an angle of pivotal movement of the jack member to the erected posture attained by movement of the vehicle body. Thus, a severe control is required to raise the front of the vehicle body by a desired amount. When the operator fails to stop the vehicle in an appropriate position, the jack member or adjacent components may be damaged due to overloading. In order to avoid this situation, the jack member must be strong enough to endure such load. To secure sufficient strength, the jack member has to be formed of an expensive material or provided with a reinforcement. This will lead to a cost increase or a complicated structure. Further, the toothed portion thrusting into the ground and acting as a pivot for the jack member in time of raising the vehicle body may badly injure the ground surface, which in many cases is turf.
In the mid-mount mower known from Japanese Patent Publication Kokai No. 2000-342040, a transverse support frame having caster-type front wheels attached to opposite ends thereof is connected in a middle position to a vehicle body to be pivotable about a longitudinal axis, and a jack device is disposed between the vehicle body and the front-wheel support frame. When this jack device operates, the front-wheel support frame pivots upward about one of the right and left front wheels to raise the front part of the vehicle body, thereby exposing the inside of the mower unit.
This jack device raises the front of the vehicle body by an upward pivotal movement of the front-wheel support frame about the longitudinal axis using one of the right and left front wheels as a fulcrum. As a result, the vehicle body could become unstable when raised, and the mower should be parked on as level a surface as possible.
In both of the prior art examples noted above, the upward pivotal movement of the jack member or the front-wheel support frame raises the front part of the vehicle body. As a result, the jack member or the front-wheel support frame must be strengthened enough to endure a bending force generated in time of raising the vehicle body. For this purpose, it may be necessary to use an expensive material or provide a reinforcing member, which will lead to a cost increase or a complicated structure.